Chain sticking in front derailleur

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  • Hey Gang,

    Can someone help solve this issue that has left me and my LBS stumped.

    My brother is just getting back in cycling and has just bought a new Cannondale Caad with Sora groupset.

    There seems to be an issue when shifting into the big chainring where the chain doesn't always land on the chainring and the chain hovers on the teeth before catching then has a tendency to intermittently jam between the chainring and the front mech and get "proper" stuck.

    I've attached an image of it getting stuck below with the original chain.

    Bikes been looked at by the shop he purchased from and my LBS and have not managed to solve the issue. I've now replaced the chain and chainrings to see if that would help and still seems to happen.

    Here's what I've also checked
    -BB axle doesn't seem to have play in it
    -Chain is not stiff on any links

    Any advice on anything else to try would be much appreciated trying to encourage him to get out on the bike and constant mechanicals aren't helping, or am I expecting too much from a fairly basic setup.

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    • IMG_20210418_114534_1.jpg
  • Not sure if this will post as well but here is a video showing the chain not quite catching on the chainring...This is with a brand new chain and chainring.

    1 Attachment

  • Did you orientate the two rings properly? Sometimes there are markings on the rings, or little notches.

    Looking at the screenshot from your video below, you can see a notch on the small chainring. Look for the one on the big chainring, and align these with each other.

  • No worries @Tijs original FSA ring did not have markings on but had pin on the correct side....Chainring has been replaced by Shimano 105.

  • It’s not a new bike is it? Looks banged up already. And the crank seems to be floating about 4cm away for the hub shell which is ‘odd’

  • Cheers for that will take a look.

  • Cheers for the reply @dubtap The bike was new but around 6 months old now (He had a few slips while learning clipless pedals)....Did think the BB axle looked on the long side but assumed as it came fitted to the bike would be correct....Looking at it the chainset has holes for a 3rd smaller chainring so could the longer axle be to accommodate an extra chainring if it was being run as a triple?

  • The clearance between the chainrings and the chainstays doesn't look too big judging from the pictures, so I don't think the axle is too long.

    As you can see the chainrings are both mounted on the inside of the spider, so how far the crankset sits from the bottom bracket shell is not really indicative of whether the axle is too long in this case.

    assumed as it came fitted to the bike would be correct

    I would agree, and wouldn't look for the problem there.

  • Cheers @Tijs just had a look and your right about that locating tab on the inner chainring isn't under the crank arm so can shuffle that round...Having a google now but is there a similar marking on the outer chainring so both rings line up?

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    • WhatsApp Image 2021-05-04 at 21.07.12.jpeg
  • that locating tab on the inner chainring isn't under the crank arm

    That doesn't really matter, what matters is the alignment with the other chainring. Inner ring orientation is only relevant when the ring has a chain catcher pin. Then it should be orientated like you said.

    is there a similar marking on the outer chainring so both rings line up?

    Is it a matching chainring set? It's best to have matching set, as they are designed to shift optimally together. Mixing and matching chainrings can have an effect on the shift quality.

    In case of a set, either the chainrings themselves have a marking/tab, or their alignment might be written down in a manual.

  • From the photo in he OP and the video screenshot I was going to say the mech is too high/far away from the rings but in the closer up photo it maybe doesn't look so bad.

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Chain sticking in front derailleur

Posted by Avatar for Benzo @Benzo